Clear Binary Blends of Aliphatic-Aromatic Polyesters and Copolyestercarbonates

ABSTRACT

The clear blends of this invention are unique compositions of matter and are prepared by blending polyesters prepared from terephthalic acid, 40 to 5 mole % 2,2,4,4-tetramethy-1,3-cyclobutanediol and 60 to 95 mole % 1,4-cyclohexanedimethanol with a copolyestercarbonate comprising a bisphenol A diol component and 50-90 mole % isophthalic acid and 0-60 mole % terephthalic acid and 0 to 60 mole % carbonic acid. The composition of the blend includes up to about 95 weight % the copolyestercarbonate. These blends have a combination of clarity and toughness making the materials particularly useful in engineering molding plastics and packaging.

FIELD OF THE INVENTION

This invention relates to the preparation of blends of polyesters from terephthalic acid, 40 to 5 mol % 2,2,4,4-tetramethy-1,3-cyclobutanediol and 60 to 95 mol % 1,4-cyclohexanedimethanol with copolyestercarbonates.

BACKGROUND OF THE INVENTION

Clear blends of two polymers are rare. Blends of polyesters containing % 2,2,4,4-tetramethy-1,3-cyclobutanediol with copolyestercarbonates provide clear blends.

SUMMARY OF THE INVENTION

These and other objects are achieved by the present polymer blend comprising (1) 5-95 weight % of a aliphatic-aromatic copolyester having repeat units 2,2,4,4, tetramethyl-1,3 cyclobutanediol, 1,4-cyclohexanedimethanol and terephthalic acid; (2) 5-95 weight % of an copolyestercarbonate comprising a bisphenol A diol component and 50-90 mole % isophthalic acid, 0-60 mole % terephthalic acid and 0 to 60 mole % carbonic acid wherein the total mole % of acid units is equal to 100 mole %.

In one embodiment, the invention relates to a polymer blend comprising:

-   (A) about 5% to about 95% by weight of at least one polyester (A)     which comprises:     -   (a) a dicarboxylic acid component comprising:         -   i) 70 to 100 mole % of terephthalic acid residues;         -   ii) 0 to 30 mole % of aromatic dicarboxylic acid residues             having up to 20 carbon atoms; and         -   iii) 0 to 10 mole % of aliphatic dicarboxylic acid residues             having up to 16 carbon atoms; and     -   (b) a glycol component comprising:         -   i) 15 to 40 mole % of             2,2,4,4-tetramethyl-1,3-cyclobutanediol residues; and         -   ii) 60 to 85 mole % of 1,4-cyclohexanedimethanol residues,     -   wherein the total mole % of the dicarboxylic acid component is         100 mole %, and the total mole % of the glycol component is 100         mole %; and -   (B) about 95% to about 5% by weight of at least one polymer (B)     comprising a copolyestercarbonate of bisphenol A diol, and     isophthalic acid, terephthalic acid, and carbonic acid;     wherein said percentages are based on the total weight of the     polymer blend.

In another embodiment, the invention relates to a polymer blend comprising:

-   (A) about 5% to about 95% by weight of at least one polyester (A)     which comprises:     -   (a) a dicarboxylic acid component comprising:         -   i) 70 to 100 mole % of terephthalic acid residues;         -   ii) 0 to 30 mole % of aromatic dicarboxylic acid residues             having up to 20 carbon atoms; and         -   iii) 0 to 10 mole % of aliphatic dicarboxylic acid residues             having up to 16 carbon atoms; and     -   (b) a glycol component comprising:         -   i) 15 to 40 mole % of             2,2,4,4-tetramethyl-1,3-cyclobutanediol residues; and         -   ii) 60 to 85 mole % of 1,4-cyclohexanedimethanol residues,     -   wherein the total mole % of the dicarboxylic acid component is         100 mole %, and the total mole % of the glycol component is 100         mole %; and -   (B) about 95% to about 5% by weight of at least one polymer (B)     comprising a copolyestercarbonate of bisphenol A diol, and 50 to 90     mole % isophthalic acid, 0 to 60 mole % terephthalic acid, and 0 to     60 mole % carbonic acid;     -   wherein said acid percentages of polymer (B) are based on a         total of 100 mole % of acid units; and         wherein said weight percentages of polymers in the blend are         based on the total weight of the polymer blend.

In yet another embodiment, the invention relates to a polymer blend comprising:

-   (A) about 5% to about 95% by weight of at least one polyester (A)     which comprises:     -   (a) a dicarboxylic acid component comprising:         -   i) 70 to 100 mole % of terephthalic acid residues;         -   ii) 0 to 30 mole % of aromatic dicarboxylic acid residues             having up to 20 carbon atoms; and         -   iii) 0 to 10 mole % of aliphatic dicarboxylic acid residues             having up to 16 carbon atoms; and     -   (b) a glycol component comprising:         -   i) 20 to 40 mole % of             2,2,4,4-tetramethyl-1,3-cyclobutanediol residues; and         -   ii) 60 to 80 mole % of 1,4-cyclohexanedimethanol residues,     -   wherein the total mole % of the dicarboxylic acid component is         100 mole %, and the total mole % of the glycol component is 100         mole %; and -   (B) about 95% to about 5% by weight of at least one polymer (B)     comprising a copolyestercarbonate of bisphenol A diol, and 35 to 50     mole % isophthalic acid residues, 1 to 10 mole % terephthalic acid     residues, and 40 to 60 mole % carbonic acid residues;     -   wherein said acid percentages of polymer (B) are based on a         total of 100 mole % of acid units; and         wherein said weight percentages of polymers in the blend are         based on the total weight of the polymer blend.

One of the objectives of this invention is to provide blends of high molecular weight polyesters comprising units of terephthalic acid, 2,2,4,4-tetramethy-1,3-cyclobutanediol and 1,4-cyclohexanedimethanol with copolyestercarbonates useful as molding plastics, fibers and films. A second objective of this invention is to provide blends useful as molding plastics, fibers, and films having excellent clarity. A third objective of this invention is to provide molding plastics, fibers, and films having good heat resistance. A fourth object of this invention is to provide a polymer blend that is miscible and clear with excellent thermal properties.

DETAILED DESCRIPTION

This invention relates to clear miscible blends of a aliphatic-aromatic copolyester of terephthalic acid, 2,2,4,4, tetramethyl-1,3 cyclobutanediol and 1,4 cyclohexanedimethanol with a copolyestercarbonate of bisphenol A diol, and isophthalic acid, terephthalic acid, and carbonic acid. Conventional blends of two polymers are not clear and typically show two glass transition temperatures. The compatible blends of this invention, on the other hand, have excellent clarity indicating miscibility and exhibit one glass transition temperature and have excellent heat resistance.

According to the present invention, therefore, is provided a clear polymer blend comprising:

(1) 5-95 weight % of a copolyester having repeat units from terephthalic acid, 2,2,4,4, tetramethyl-1,3 cyclobutanediol (trans or cis or mixtures thereof) and 1,4 cyclohexanedimethanol(CHDM) (trans or cis or mixtures thereof) wherein the CHDM content is between 60 to 95 mole % of the total glycol component.

(2) 5-95 weight % of a copolyestercarbonate of bisphenol A diol, and isophthalic acid, terephthalic acid, and carbonic acid.

For embodiments of the invention, the copolyesters useful in the polymer blends of the invention may exhibit at least one of the following inherent viscosities as determined in 60/40 (wt/wt) phenol/tetrachloroethane at a concentration of 0.25 g/50 ml at 25° C.: 0.45 to 1.2 dL/g; 0.45 to 1.1 dL/g; 0.45 to 1 dL/g; 0.45 to 0.98 dL/g; 0.45 to 0.95 dL/g; 0.45 to 0.90 dL/g; 0.45 to 0.85 dL/g; 0.45 to 0.80 dL/g; 0.45 to 0.75 dL/g; 0.45 to less than 0.75 dL/g; 0.45 to 0.72 dL/g; 0.45 to 0.70 dL/g; 0.45 to less than 0.70 dL/g; 0.45 to 0.68 dL/g; 0.45 to less than 0.68 dL/g; 0.45 to 0.65 dL/g; 0.50 to 1.2 dL/g; 0.50 to 1.1 dL/g; 0.50 to 1 dL/g; 0.50 to less than 1 dL/g; 0.50 to 0.98 dL/g; 0.50 to 0.95 dL/g; 0.50 to 0.90 dL/g; 0.50 to 0.85 dL/g; 0.50 to 0.80 dL/g; 0.50 to 0.75 dL/g; 0.50 to less than 0.75 dL/g; 0.50 to 0.72 dL/g; 0.50 to 0.70 dL/g; 0.50 to less than 0.70 dL/g; 0.50 to 0.68 dL/g; 0.50 to less than 0.68 dL/g; 0.50 to 0.65 dL/g; 0.55 to 1.2 dL/g; 0.55 to 1.1 dL/g; 0.55 to 1 dL/g; 0.55 to less than 1 dL/g; 0.55 to 0.98 dL/g; 0.55 to 0.95 dL/g; 0.55 to 0.90 dL/g; 0.55 to 0.85 dL/g; 0.55 to 0.80 dL/g; 0.55 to 0.75 dL/g; 0.55 to less than 0.75 dL/g; 0.55 to 0.72 dL/g; 0.55 to 0.70 dL/g; 0.55 to less than 0.70 dL/g; 0.55 to 0.68 dL/g; 0.55 to less than 0.68 dL/g; 0.55 to 0.67 dL/g; 0.55 to 0.65 dL/g; 0.58 to 1.2 dL/g; 0.58 to 1.1 dL/g; 0.58 to 1 dL/g; 0.58 to less than 1 dL/g; 0.58 to 0.98 dL/g; 0.58 to 0.95 dL/g; 0.58 to 0.90 dL/g; 0.58 to 0.85 dL/g; 0.58 to 0.80 dL/g; 0.58 to 0.75 dL/g; 0.58 to less than 0.75 dL/g; 0.58 to 0.72 dL/g; 0.58 to 0.70 dL/g; 0.58 to less than 0.70 dL/g; 0.58 to 0.68 dL/g; 0.58 to less than 0.68 dL/g; 0.58 to 0.65 dL/g; 0.60 to 1.2 dL/g; 0.60 to 1.1 dL/g; 0.60 to 1 dL/g; 0.60 to less than 1 dL/g; 0.60 to 0.98 dL/g; 0.60 to 0.95 dL/g; 0.60 to 0.90 dL/g; 0.60 to 0.85 dL/g; 0.60 to 0.80 dL/g; 0.60 to 0.75 dL/g; 0.60 to less than 0.75 dL/g; 0.60 to 0.72 dL/g; 0.60 to 0.70 dL/g; 0.60 to less than 0.70 dL/g; 0.60 to 0.68 dL/g; 0.60 to less than 0.68 dL/g; 0.60 to 0.65 dL/g; 0.60 to 0.64 dL/g; 0.61 to 0.68 dL/g; 0.64 to 0.65 dL/g; 0.65 to 1.2 dL/g; 0.65 to 1.1 dL/g; 0.65 to 1 dL/g; 0.65 to less than 1 dL/g; 0.65 to 0.98 dL/g; 0.65 to 0.95 dL/g; 0.65 to 0.90 dL/g; 0.65 to 0.85 dL/g; 0.65 to 0.80 dL/g; 0.65 to 0.75 dL/g; 0.65 to less than 0.75 dL/g; 0.65 to 0.72 dL/g; 0.65 to 0.70 dL/g; 0.65 to less than 0.70 dL/g; 0.68 to 1.2 dL/g; 0.68 to 1.1 dL/g; 0.68 to 1 dL/g; 0.68 to less than 1 dL/g; 0.68 to 0.98 dL/g; 0.68 to 0.95 dL/g; 0.68 to 0.90 dL/g; 0.68 to 0.85 dL/g; 0.68 to 0.80 dL/g; 0.68 to 0.75 dL/g; 0.68 to less than 0.75 dL/g; 0.68 to 0.72 dL/g; 0.69 to 0.75 dL/g; 0.76 dL/g to 1.2 dL/g; 0.76 dL/g to 1.1 dL/g; 0.76 dL/g to 1 dL/g; 0.76 dL/g to less than 1 dL/g; 0.76 dL/g to 0.98dL/g; 0.76 dL/g to 0.95 dL/g; 0.76 dL/g to 0.90 dL/g 0.80 dL/g to 1.2 dL/g; 0.80 dL/g to 1.1 dL/g; 0.80 dL/g to 1 dL/g; 0.80 dL/g to less than 1 dL/g; 0.80 dL/g to 1.2 dL/g; 0.80 dL/g to 0.98dL/g; 0.80 dL/g to 0.95 dL/g; 0.80 dL/g to 0.90 dL/g.

The diacids useful in the present invention may comprise from about 65 to 100 mole percent, preferably 80 to 100 mole percent, more preferably, 85 to 100 mole percent, even more preferably, 90 to 100 mole percent, and further 95 to 100 mole percent, of dicarboxylic acids selected from the group consisting of terephthalic acid residues, isophthalic acids, or mixtures thereof. For example, the polyester may comprise about 70 to about 100 mole % of diacid residues from terephthalic acid and 0 to about 30 mole % diacid residues from isophthalic acid (in one embodiment, about 0.1 to 30 mole percent isophthalic acid.

Copolyesters of the polymer blends of the invention also may further comprise from about 0 to about 30 mole percent, preferably 0 to 10 mole percent, and more preferably, 0.1 to 10 mole percent of the residues of one or more modifying diacids containing about 2 to about 20 carbon atoms (not terephthalic acid and/or isophthalic acid). Examples of modifying diacids containing about 2 to about 20 carbon atoms that may be used include but are not limited to aliphatic dicarboxylic acids, alicyclic dicarboxylic acids, aromatic dicarboxylic acids, or mixtures of two or more of these acids. Specific examples of modifying dicarboxylic acids include, but are not limited to, one or more of succinic acid, glutaric acid, adipic acid, suberic acid, sebacic acid, azelaic acid, dimer acid, sulfoisophthalic acid. Additional examples of modifying diacids are fumaric, maleic, itaconic, 1,3-cyclohexanedicarboxylic, diglycolic, 2,5-norbornanedicarboxyclic, phthalic acid, diphenic, 4,4′-oxydibenzoic, and 4,4′-sulfonyldibenzoic. Other examples of modifying dicarboxylic acid residues include but are not limited to naphthalenedicarboxylic acid and 1,4-cyclohexanedicarboxylic acid. Any of the various isomers of naphthalenedicarboxylic acid or mixtures of isomers may be used, but the 1,4-, 1,5-, 2,6-, and 2,7-isomers are preferred. Cycloaliphatic dicarboxylic acids such as, for example, 1,4-cyclohexanedicarboxylic acid may be present at the pure cis or trans isomer or as a mixture of cis and trans isomers.

For the copolyesters of the present invention, the molar ratio of cis/trans 2,2,4,4-tetramethyl-1,3-cyclobutanediol can vary from the pure form of each and mixtures thereof. In certain embodiments, the molar percentages for cis and/or trans 2,2,4,4,-tetramethyl-1,3-cyclobutanediol are greater than 50 mole % cis and less than 50 mole % trans; or greater than 55 mole % cis and less than 45 mole % trans; or 30 to 70 mole % cis and 70 to 30 mole % trans; or 40 to 60 mole % cis and 60 to 40 mole % trans; or 50 to 70 mole % trans and 50 to 30 mole % cis; or 50 to 70 mole % cis and 50 to 30 mole % trans; or 60 to 70 mole % cis and 30 to 40 mole % trans; or greater than 70 mole % cis and less than 30 mole % trans; wherein the total mole percentages for cis- and trans-2,2,4,4-tetramethyl-1,3-cyclobutanediol is equal to 100 mole %. In an additional embodiment, the molar ratio of cis/trans 2,2,4,4-tetramethyl-1,3-cyclobutanediol can vary within the range of 50/50 to 0/100, for example, between 40/60 to 20/80.

The cyclohexanedimethanol may be cis, trans, or a mixture thereof, for example, a cis/trans ratio of 60:40 to 40:60 or a cis/trans ratio of 70:30 to 30:70. In another embodiment, the trans-cyclohexanedimethanol can be present in an amount of 60 to 80 mole % and the cis-cyclohexanedimethanol can be present in an amount of 20 to 40 mole % wherein the total percentages of cis-cyclohexanedimethanol and trans-cyclohexanedimethanol is equal to 100 mole %. In particular embodiments, the trans-cyclohexanedimethanol can be present in an amount of 60 mole % and the cis-cyclohexanedimethanol can be present in an amount of 40 mole %. In particular embodiments, the trans-cyclohexanedimethanol can be present in an amount of 70 mole % and the cis-cyclohexanedimethanol can be present in an amount of 30 mole %. Any of 1,1-, 1,2-, 1,3-, 1,4-isomers of cyclohexanedimethanol or mixtures thereof may be present in the glycol component of this invention.

The glycol portion of these aliphatic-aromatic copolyesters may contain up to 30 mol % or up to 10 mole %, up to 5 mol % of another glycol containing 2 to 16 carbon atoms. Examples of suitable glycols include ethylene glycol, 1,2-propanediol, 1,3-propanediol, neopentyl glycol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, or p-xylene glycol. The polymers may also be modified with polyethylene glycols or polytetramethylene glycols. Examples of esters of the dicarboxylic acids useful in this invention include the dimethyl, dipropyl, diisopropyl, dibutyl, diphenyl etc.

In other aspects of the invention, the glycol component for the copolyester useful in blends of the invention include but are not limited to at least one of the following combinations of ranges: 5 to 99 mole % TMCD and 1 to 95 mole % CHDM; 5 to 95 mole % TMCD and 5 to 95 mole % CHDM; 5 to 90 mole % TMCD and 10 to 95 mole % CHDM; 5 to 85 mole % TMCD and 15 to 95 mole % CHDM; 5 to 80 mole % TMCD and 20 to 95 mole % CHDM, 5 to 75 mole % TMCD and 25 to 95 mole % CHDM; 5 to 70 mole % TMCD and 30 to 95 mole % CHDM; 5 to 65 mole % TMCD and 35 to 95 mole % CHDM; 5 to 60 mole % TMCD and 40 to 95 mole % CHDM; 5 to 55 mole % TMCD and 45 to 95 mole % CHDM; and 5 to 50 mole % TMCD and 50 to 95 mole % CHDM.

In other aspects of the invention, the glycol component for the copolyester useful in the polymer blends of the invention include but are not limited to at least one of the following combinations of ranges: 5 to less than 50 mole % TMCD and greater than 50 to 95 mole % CHDM; 5 to 45 mole % TMCD and 55 to 95 mole % CHDM; 5 to 40 mole % TMCD and 60 to 95 mole % CHDM; 5 to 35 mole % TMCD and 65 to 95 mole % CHDM; 5 to less than 35 mole % TMCD and greater than 65 to 95 mole % CHDM; 5 to 30 mole % TMCD and 70 to 95 mole % CHDM; 5 to 25 mole % TMCD and 75 to 95 mole % CHDM; 5 to 20 mole % TMCD and 80 to 95 mole % CHDM; 5 to 15 mole % TMCD and 85 to 95 mole % CHDM; 5 to 10 mole % TMCD and 90 to 95 mole % CHDM; greater than 5 to less than 10 mole % TMCD and less than 90 to greater than 95 mole % CHDM; 5.5 mole % to 9.5 mole % TMCD and 94.5 mole % to 90.5 mole % CHDM; and 6 to 9 mole % TMCD and 94 to 91 mole % CHDM.

In other aspects of the invention, the glycol component for the copolyesters useful in the polymer blends of the invention include but are not limited to at least one of the following combinations of ranges: 10 to 99 mole % TMCD and 1 to 90 mole % CHDM; 10 to 95 mole % TMCD and 5 to 90 mole % CHDM; 10 to 90 mole % TMCD and 10 to 90 mole % CHDM; 10 to 85 mole % TMCD and 15 to 90 mole % CHDM; 10 to 80 mole % TMCD and 20 to 90 mole % CHDM; 10 to 75 mole % TMCD and 25 to 90 mole % CHDM; 10 to 70 mole % TMCD and 30 to 90 mole % CHDM; 10 to 65 mole % TMCD and 35 to 90 mole % CHDM; 10 to 60 mole % TMCD and 40 to 90 mole % CHDM; 10 to 55 mole % TMCD and 45 to 90 mole % CHDM; 10 to 50 mole % TMCD and 50 to 90 mole % CHDM; 10 to less than 50 mole % TMCD and greater than 50 to 90 mole % CHDM; 10 to 45 mole % TMCD and 55 to 90 mole % CHDM; 10 to 40 mole % TMCD and 60 to 90 mole % CHDM; 10 to 35 mole % TMCD and 65 to 90 mole % CHDM; 10 to less than 35 mole % TMCD and greater than 65 to 90% CHDM; 10 to 30 mole % TMCD and 70 to 90 mole % CHDM; 10 to 25 mole % TMCD and 75 to 90 mole % CHDM; 10 to 20 mole % TMCD and 80 to 90 mole % CHDM; and 10 to 15 mole % TMCD and 85 to 90 mole % CHDM.

In other aspects of the invention, the glycol component for the copolyester useful in the polymer blends of the invention include but are not limited to at least one of the following combinations of ranges: 15 to 99 mole % TMCD and 1 to 85 mole % CHDM; 15 to 95 mole % TMCD and 5 to 85 mole % CHDM; 15 to 90 mole % TMCD and 10 to 85 mole % CHDM; 15 to 85 mole % TMCD and 15 to 85 mole % CHDM; 15 to 80 mole % TMCD and 20 to 85 mole % CHDM; 15 to 75 mole % TMCD and 25 to 85 mole % CHDM; 15 to 70 mole % TMCD and 30 to 85 mole % CHDM; 15 to 65 mole % TMCD and 35 to 85 mole % CHDM; 15 to 60 mole % TMCD and 40 to 85 mole % CHDM; 15 to 55 mole % TMCD and 45 to 85 mole % CHDM; 15 to 50 mole % TMCD and 50 to 85 mole % CHDM; 15 to less than 50 mole % TMCD and greater than 50 to 85 mole % CHDM; 15 to 45 mole % TMCD and 55 to 85 mole % CHDM; 15 to 40 mole % TMCD and 60 to 85 mole % CHDM; 15 to 35 mole % TMCD and 65 to 85 mole % CHDM; 15 to 30 mole % TMCD and 70 to 85 mole % CHDM; 15 to 25 mole % TMCD and 75 to 85 mole % CHDM; and 15 to 24 mole % TMCD and 76 to 85 mole % CHDM.

In other aspects of the invention, the glycol component for the copolyester useful in the polymer blends of the invention include but are not limited to at least one of the following combinations of ranges: 20 to 99 mole % TMCD and 1 to 80 mole % CHDM; 20 to 95 mole % TMCD and 5 to 80 mole % CHDM; 20 to 90 mole % TMCD and 10 to 80 mole % CHDM; 20 to 85 mole % TMCD and 15 to 80 mole % CHDM; 20 to 80 mole % TMCD and 20 to 80 mole % CHDM; 20 to 75 mole % TMCD and 25 to 80 mole % CHDM; 20 to 70 mole % TMCD and 30 to 80 mole % CHDM; 20 to 65 mole % TMCD and 35 to 80 mole % CHDM; 20 to 60 mole % TMCD and 40 to 80 mole % CHDM; 20 to 55 mole % TMCD and 45 to 80 mole % CHDM; 20 to 50 mole % TMCD and 50 to 80 mole % CHDM; 20 to less than 50 mole % TMCD and greater than 50 to 80 mole % CHDM; 20 to 45 mole % TMCD and 55 to 80 mole % CHDM; 20 to 40 mole % TMCD and 60 to 80 mole % CHDM; 20 to 35 mole % TMCD and 65 to 80 mole % CHDM; 20 to 30 mole % TMCD and 70 to 80 mole % CHDM; and 20 to 25 mole % TMCD and 75 to 80 mole % CHDM.

In other aspects of the invention, the glycol component for the copolyesters useful in the polymer blends of the invention include but are not limited to at least one of the following combinations of ranges: 25 to 99 mole % TMCD and 1 to 75 mole % CHDM; 25 to 95 mole % TMCD and 5 to 75 mole % CHDM; 25 to 90 mole % TMCD and 10 to 75 mole % CHDM; 25 to 85 mole % TMCD and 15 to 75 mole % CHDM; 25 to 80 mole % TMCD and 20 to 75 mole % CHDM; 25 to 75 mole % TMCD and 25 to 75 mole % CHDM; 25 to 70 mole % TMCD and 30 to 75 mole % CHDM; 25 to 65 mole % TMCD and 35 to 75 mole % CHDM; 25 to 60 mole % TMCD and 40 to 75 mole % CHDM; 25 to 55 mole % TMCD and 45 to 75 mole % CHDM; 25 to 50 mole % TMCD and 50 to 75 mole % CHDM; 25 to less than 50 mole % TMCD and greater than 50 to 75 mole % CHDM; 25 to 45 mole % TMCD and 55 to 75 mole % CHDM; 25 to 40 mole % TMCD and 60 to 75 mole % CHDM; 25 to 35 mole % TMCD and 65 to 75 mole % CHDM; and 25 to 30 mole % TMCD and 70 to 75 mole % CHDM.

In other aspects of the invention, the glycol component for the copolyester useful in the blends of the invention include but are not limited to at least one of the following combinations of ranges: 30 to 99 mole % TMCD and 1 to 70 mole % CHDM; 30 to 95 mole % TMCD and 5 to 70 mole % CHDM; 30 to 90 mole % TMCD and 10 to 70 mole % CHDM; 30 to 85 mole % TMCD and 15 to 70 mole % CHDM; 30 to 80 mole % TMCD and 20 to 70 mole % CHDM; 30 to 75 mole % TMCD and 25 to 70 mole % CHDM; 30 to 70 mole % TMCD and 30 to 70 mole % CHDM; 30 to 65 mole % TMCD and 35 to 70 mole % CHDM; 30 to 60 mole % TMCD and 40 to 70 mole % CHDM; 30 to 55 mole % TMCD and 45 to 70 mole % CHDM; 30 to 50 mole % TMCD and 50 to 70 mole % CHDM; 30 to less than 50 mole % TMCD and greater than 50 to 70 mole % CHDM; 30 to 45 mole % TMCD and 55 to 70 mole % CHDM; 30 to 40 mole % TMCD and 60 to 70 mole % CHDM; 30 to 35 mole % TMCD and 65 to 70 mole % CHDM; 31 to 35 mole % TMCD and 65 to 69 mole % CHDM.

In other aspects of the invention, the glycol component for the copolyesters useful in the blends of the invention include but are not limited to at least one of the following combinations of ranges: 35 to 99 mole % TMCD and 1 to 65 mole % CHDM; 35 to 95 mole % TMCD and 5 to 65 mole % CHDM; 35 to 90 mole % TMCD and 10 to 65 mole % CHDM; 35 to 85 mole % TMCD and 15 to 65 mole % CHDM; 35 to 80 mole % TMCD and 20 to 65 mole % CHDM; 35 to 75 mole % TMCD and 25 to 65 mole % CHDM; 35 to 70 mole % TMCD and 30 to 65 mole % CHDM; 35 to 65 mole % TMCD and 35 to 65 mole % CHDM; 35 to 60 mole % TMCD and 40 to 65 mole % CHDM; 35 to 55 mole % TMCD and 45 to 65 mole % CHDM; 35 to 50 mole % TMCD and 50 to 65 mole % CHDM; 35 to less than 50 mole % TMCD and greater than 50 to 65 mole % CHDM; 35 to 45 mole % TMCD and 55 to 65 mole % CHDM; 35 to 40 mole % TMCD and 60 to 65 mole % CHDM.

In other aspects of the invention, the glycol component for the copolyester useful in the blends of the invention include but are not limited to at least one of the following combinations of ranges: 40.1 to 100 mole % TMCD and 1 to 59.9 mole % CHDM 40 to 99 mole % TMCD and 1 to 60 mole % CHDM; 40 to 95 mole % TMCD and 5 to 60 mole % CHDM; 40 to 90 mole % TMCD and 10 to 60 mole % CHDM; 40 to 85 mole % TMCD and 15 to 60 mole % CHDM; 40 to 80 mole % TMCD and 20 to 60 mole % CHDM; 40 to 75 mole % TMCD and 25 to 60 mole % CHDM; 40 to 70 mole % TMCD and 30 to 60 mole % CHDM; 40 to 65 mole % TMCD and 35 to 60 mole % CHDM; 40 to 60 mole % TMCD and 40 to 60 mole % CHDM; 40 to 55 mole % TMCD and 45 to 60 mole % CHDM; 40 to less than 50 mole % TMCD and greater than 50 to 60 mole % CHDM; 40 to 50 mole % TMCD and 50 to 60 mole % CHDM; and 40 to 45 mole % TMCD and 55 to 60 mole % CHDM.

In other aspects of the invention, the glycol component for the copolyesters useful in the blends of the invention include but are not limited to at least one of the following combinations of ranges: 45 to 100 mole % TMCD and 0 to 55 mole % CHDM; 45 to 99 mole % TMCD and 1 to 55 mole % CHDM; 45 to 95 mole % TMCD and 5 to 55 mole % CHDM; 45 to 90 mole % TMCD and 10 to 55 mole % CHDM; 45 to 85 mole % TMCD and 15 to 55 mole % CHDM; 45 to 80 mole % TMCD and 20 to 55 mole % CHDM; 45 to 75 mole % TMCD and 25 to 55 mole % CHDM; 45 to 70 mole % TMCD and 30 to 55 mole % CHDM; 45 to 65 mole % TMCD and 35 to 55 mole % CHDM; 45 to 60 mole % TMCD and 40 to 55 mole % CHDM; greater than 45 to 55 mole % TMCD and 45 to less than 55 mole % CHDM; 45 to 55 mole % TMCD and 45 to 55 mole % CHDM; and 45 to 50 mole % TMCD and 50 to 60 mole % CHDM.

In other aspects of the invention, the glycol component for the copolyesters useful in the polymer blends of the invention include but are not limited to at least one of the following combinations of ranges: 55 to 99 mole % TMCD and 1 to 45 mole % CHDM; 55 to 95 mole % TMCD and 5 to 45 mole % CHDM; 55 to 90 mole % TMCD and 10 to 45 mole % CHDM; 55 to 85 mole % TMCD and 15 to 45 mole % CHDM; 55 to 80 mole % TMCD and 20 to 45 mole % CHDM; 55 to 75 mole % TMCD and 25 to 45 mole % CHDM; 55 to 70 mole % TMCD and 30 to 45 mole % CHDM; 55 to 65 mole % TMCD and 35 to 45 mole % CHDM; and 55 to 60 mole % TMCD and 40 to 45 mole % CHDM.

In other aspects of the invention, the glycol component for the copolyesters useful in the polymer blends of the invention include but are not limited to at least one of the following combinations of ranges: 60 to 99 mole % TMCD and 1 to 40 mole % CHDM; 60 to 95 mole % TMCD and 5 to 40 mole % CHDM; 60 to 90 mole % TMCD and 10 to 40 mole % CHDM; 60 to 85 mole % TMCD and 15 to 40 mole % CHDM; 60 to 80 mole % TMCD and 20 to 40 mole % CHDM; 60 to 75 mole % TMCD and 25 to 40 mole % CHDM; and 60 to 70 mole % TMCD and 30 to 40 mole % CHDM.

In other aspects of the invention, the glycol component for the polyesters useful in the polymer blends of the invention include but are not limited to at least one of the following combinations of ranges: 65 to 99 mole % TMCD and 1 to 35 mole % CHDM; 65 to 95 mole % TMCD and 5 to 35 mole % CHDM; 65 to 90 mole % TMCD and 10 to 35 mole % CHDM; 65 to 85 mole % TMCD and 15 to 35 mole % CHDM; 65 to 80 mole % TMCD and 20 to 35 mole % CHDM; 65 to 75 mole % TMCD and 25 to 35 mole % CHDM; and 65 to 70 mole % TMCD and 30 to 35 mole % CHDM.

The copolyesters in the present invention comprise from about 0 to about 10 or 0.01 to about 10 weight percent (wt %), or from about 0.05 to about 5 weight percent, or from about 0.01 to 1 weight percent, or 0.1 to 0.7 weight percent, based on the total weight of the polyester, of one or more residues of a branching monomer having 3 or more carboxyl substituents, hydroxyl substituents, or a combination thereof. Examples of branching monomers include, but are not limited to, multifunctional acids or glycols such as trimellitic acid, trimellitic anhydride, pyromellitic dianhydride, trimethylolpropane, glycerol, pentaerythritol, citric acid, tartaric acid, 3-hydroxyglutaric acid and the like. In one embodiment, the branching monomer residues comprise about 0.1 to about 0.7 mole percent of one or more residues of: trimellitic anhydride, pyromellitic dianhydride, glycerol, sorbitol, 1,2,6-hexanetriol, pentaerythritol, trimethylolethane, or trimesic acid. The branching monomer may be added to the polyester reaction mixture or blended with the polyester in the form of a concentrate as described, for example, in U.S. Pat. Nos. 5,654,347 and 5,696,176.

The polyesters present in the instant invention are readily prepared from the appropriate dicarboxylic acids, esters, anhydrides, or salts, the appropriate diol or diol mixtures, and optionally branching monomers using typical polycondensation reaction conditions. They may be made by continuous, semi-continuous, and batch modes of operation and may utilize a variety of reactor types. Examples of suitable reactor types include, but are not limited to, stirred tank, continuous stirred tank, slurry, tubular, wiped-film, falling film, or extrusion reactors. The term “continuous” as used herein means a process wherein reactants are introduced and products withdrawn simultaneously in an uninterrupted manner. By “continuous” it is meant that the process is substantially or completely continuous in operation in contrast to a “batch” process. “Continuous” is not meant in any way to prohibit normal interruptions in the continuity of the process due to, for example, start-up, reactor maintenance, or scheduled shut down periods. The term “batch” process as used herein means a process wherein all the reactants are added to the reactor and then processed according to a predetermined course of reaction during which no material is fed or removed into the reactor. The term “semicontinuous” means a process where some of the reactants are charged at the beginning of the process and the remaining reactants are fed continuously as the reaction progresses. Alternatively, a semicontinuous process may also include a process similar to a batch process in which all the reactants are added at the beginning of the process except that one or more of the products are removed continuously as the reaction progresses.

The polyesters included in the present invention are prepared by procedures known to persons skilled in the art. The reaction of the diol, dicarboxylic acid, and optional branching monomer components may be carried out using conventional polyester polymerization conditions. For example, when preparing the polyester by means of an ester interchange reaction, i.e., from the ester form of the dicarboxylic acid components, the reaction process may comprise two steps. In the first step, the diol component and the dicarboxylic acid component, such as, for example, dimethyl terephthalate, are reacted at elevated temperatures, typically, about 150° C. to about 250° C. for about 0.5 to about 8 hours at pressures ranging from about 0.0 kPa gauge to about 414 kPa gauge (60 pounds per square inch, “psig”). Preferably, the temperature for the ester interchange reaction ranges from about 180° C. to about 230° C. for about 1 to about 4 hours while the preferred pressure ranges from about 103 kPa gauge (15 psig) to about 276 kPa gauge (40 psig). Thereafter, the reaction product is heated under higher temperatures and under reduced pressure to form the polyester with the elimination of diol, which is readily volatilized under these conditions and removed from the system. This second step, or polycondensation step, is continued under higher vacuum and a temperature which generally ranges from about 230° C. to about 350° C., preferably about 250° C. to about 310° C. and, most preferably, about 260° C. to about 290° C. for about 0.1 to about 6 hours, or preferably, for about 0.2 to about 2 hours, until a polymer having the desired degree of polymerization, as determined by inherent viscosity, is obtained. The polycondensation step may be conducted under reduced pressure which ranges from about 53 kPa (400 torr) to about 0.013 kPa (0.1 torr). Stirring or appropriate conditions are used in both stages to ensure adequate heat transfer and surface renewal of the reaction mixture. The reaction rates of both stages are increased by appropriate catalysts such as, for example, alkoxy titanium compounds, alkali metal hydroxides and alcoholates, salts of organic carboxylic acids, alkyl tin compounds, metal oxides, and the like. A three-stage manufacturing procedure, similar to that described in U.S. Pat. No. 5,290,631, may also be used, particularly when a mixed monomer feed of acids and esters is employed.

To ensure that the reaction of the diol component and dicarboxylic acid component by an ester interchange reaction is driven to completion, it is sometimes desirable to employ about 1.05 to about 2.5 moles of diol component to one mole dicarboxylic acid component. Persons of skill in the art will understand, however, that the ratio of diol component to dicarboxylic acid component is generally determined by the design of the reactor in which the reaction process occurs.

In the preparation of polyester by direct esterification, i.e., from the acid form of the dicarboxylic acid component, polyesters are produced by reacting the dicarboxylic acid or a mixture of dicarboxylic acids with the diol component or a mixture of diol components and the branching monomer component. The reaction is conducted at a pressure of from about 7 kPa gauge (1 psig) to about 1379 kPa gauge (200 psig), preferably less than 689 kPa (100 psig) to produce a low molecular weight polyester product having an average degree of polymerization of from about 1.4 to about 10. The temperatures employed during the direct esterification reaction typically range from about 180° C. to about 280° C., more preferably ranging from about 220° C. to about 270° C. This low molecular weight polymer may then be polymerized by a polycondensation reaction. Examples of the catalyst materials that may be used in the synthesis of the polyesters utilized in the present invention may include but are not limited to tin, titanium, manganese, zinc, cobalt, antimony, gallium, lithium, calcium, silicon and germanium. Such catalyst systems are described in U.S. Pat. Nos. 3,907,754, 3,962,189, 4,010,145, 4,356,299, 5,017,680, 5,668,243 and 5,681,918, herein incorporated by reference in their entirety. The amount of catalytic metal used may range from about 5 to 100 ppm but the use of catalyst concentrations of about 5 to about 35 ppm titanium is preferred in order to provide polyesters having good color, thermal stability and electrical properties. Phosphorus compounds frequently are used in combination with the catalyst metals and any of the phosphorus compounds normally used in making polyesters may be used. Up to about 100 ppm phosphorus typically may be used.

Polyestercarbonate resins which are suitable for use in the present invention are known in the art and are generally commercially available. These polyestercarbonates may be prepared by a variety of conventional and well known processes which include melt polymerization, interfacial polymerization, etc. Suitable processes for preparing the polycarbonates of the present invention are described in any of the following Patent Cooperation Treaty Publications: WO 01/18104 A1 (Shakhnovich et al., 3/15/2001); 01/32741 A1, (Davis et al. 5/10/2001) 01/32742 A1, (Banach et al. 5/10/2001); and 01/32743 A1 (Banach et al. 5/10/2001).

The polyestercarbonates which are used in the present invention are derived from Bisphenol A, isophthalic acid, terephthalic acid, and carbonic acid. A commercial aromatic polyester product line is sold by General Electric under the trade name Lexan 4000 series. The acid portion of the aromatic polyester may contain from 0 to 50 mole % carbonic acid, 0 to 60 mole % terephthalic acid and from 50 to 95 mole % isophthalic acid. The inherent viscosity of the polyestercarbonate can vary from about 0.3 dL/gram to about 0.7 dl/gram, but preferably should be in the range from 0.5-0.6 dL/gram.

The compositions of this invention are prepared by any conventional mixing methods. For example, a preferred method comprises mixing the aliphatic-aromatic and copolyestercarbonate in powder or granular form in an extruder and extruding the mixture into strands, chopping the strands into pellets and molding the pellets into the desired article.

It should, of course be obvious to those skilled in the art that other additives may be included in the present compositions. These additives include plasticizers, pigments flame retardant additives, reinforcing agents such as glass fibers, stabilizers, processing aids, impact modifiers, etc.

The blends of the invention may comprise additional polymeric components. Suitable examples of the additional polymeric components include, but are not limited to, nylon; polyesters different than those described herein; polyamides such as ZYTEL® from DuPont; polystyrene; polystyrene copolymers; styrene acrylonitrile copolymers; acrylonitrile butadiene styrene copolymers; poly(methylmethacrylate); acrylic copolymers; poly(ether-imides) such as ULTEM® (a poly(ether-imide) from General Electric); polyphenylene oxides such as poly(2,6-dimethylphenylene oxide) or poly(phenylene oxide)/polystyrene blends such as NORYL 1000® (a blend of poly(2,6-dimethylphenylene oxide) and polystyrene resins from General Electric); polyphenylene sulfides; polyphenylene sulfide/sulfones; poly(ester-carbonates); polycarbonates such as LEXAN® (a polycarbonate from General Electric); polysulfones; polysulfone ethers; and poly(ether-ketones) of aromatic dihydroxy compounds; or mixtures of any of the foregoing polymers.

All polymer blends (also intended to encompass the word “mixtures”) of the invention can be prepared by conventional processing techniques known in the art, such as melt blending or solution blending. The compositions of this invention are prepared by any conventional mixing methods. For example, in one embodiment, the blending method comprises mixing the aliphatic-aromatic and aliphatic polyester in powder or granular form in an extruder and extruding the mixture into strands, chopping the strands into pellets and molding the pellets into the desired article.

In addition, the polyester blends of the invention may also contain from 0.01 to 25% by weight of the overall composition common additives such as colorants, dyes, mold release agents, flame retardants, plasticizers, nucleating agents, stabilizers, including but not limited to, UV stabilizers, thermal stabilizers and/or reaction products thereof, fillers, and impact modifiers. Examples of typical commercially available impact modifiers well known in the art and useful in this invention include, but are not limited to, ethylene/propylene terpolymers, functionalized polyolefins such as those containing methyl acrylate and/or glycidyl methacrylate, styrene-based block copolymeric impact modifiers, and various acrylic core/shell type impact modifiers. Residues of such additives are also contemplated as part of the polyester composition

Reinforcing materials may be useful in the polymer blends of this invention. The reinforcing materials may include, but are not limited to, carbon filaments, silicates, mica, clay, talc, titanium dioxide, Wollastonite, glass flakes, glass beads and fibers, and polymeric fibers and combinations thereof. In one embodiment, the reinforcing materials include glass, such as, fibrous glass filaments, mixtures of glass and talc, glass and mica, and glass and polymeric fibers.

In one embodiment, the copolyesters useful in the invention as well as the blends of the invention can be visually clear. The term “visually clear” is defined herein as an appreciable absence of cloudiness, haziness, and/or muddiness, when inspected visually. Notched Izod impact strength, as described in ASTM D256, is a common method of measuring toughness.

This invention can be further illustrated by the following examples of preferred embodiments thereof, although it will be understood that these examples are included merely for purposes of illustration and are not intended to limit the scope of the invention unless otherwise specifically indicated.

EXAMPLES

The inherent viscosity of the polyesters was determined in 60/40 (wt/wt) phenol/tetrachloroethane at a concentration of 0.5 g/100 ml at 25° C. The glass transition temperatures were determined using a TA 2920 differential scanning calorimeter (DSC) at a scan rate of 20° C. The composition of the neat resins was determined by proton nuclear magnetic resonance spectroscopy (NMR). The miscibility of the blends was determined by the presence of a single glass transition and clarity of molded bars.

Example 1

The aliphatic-aromatic copolyester used contained terephthalic acid, 25.1 mol % 2,2,4,4, tetramethyl-1,3 cyclobutanediol (50.4 mol % cis isomer), 74.9% cyclohexanedimethanol. The inherent viscosity was measured to be 0.66. The copolyestercarbonate used consisted of bisphenol A diol, 51.6 mol % carbonic acid, 44.6 mol % isophthalic acid, and 3.7 mol % terephthalic acid. The inherent viscosity was measured to be 0.56.

The aliphatic-aromatic copolyester was dried at 90° C. and the copolyestercarbonate was dried at 120° C. Blends were prepared in a 19 mm Leistritz twin screw extruder. The polyesters were premixed by tumble blending and fed into the extruder and the extruded strand was pelletized. The pellets were injection molded into parts on a Toyo 90 injection molding machine. The extruder was run at 350 rpms at a feed rate to give a machine torque between 80-100%. Processing temperatures used were in the range of 270° C. to 300° C. The compositions and properties of the blends are shown in Table 1.

Heat deflection temperature, at 264 psi, was determined according to ASTM D648. Flexural modulus and flexural strength were determined according to ASTM D790. Tensile properties were determined according to ASTM D638.

TABLE 1 UNITS % Aliphatic-aromatic polyester % 100 90 80 70 50 30 0 % Copolyester carbonate % 0 10 20 30 50 70 100 Heat Deflection Temperature 264 Psi (deg C.) 82 89 95 99 112 122 143 Tensile Strength MPa 44 46 49 52 56 61 65 Tensile Break Elongation % 141 147 93 98 76 64 88 Flexural Modulus MPa 1427 1485 1571 1624 1725 1842 1948 Flexural Strength MPa 59 63 67 70 77 85 93 DSC Tg (Second Cycle) ° C. 109 114 118 123 132 145 163 Visual Clarity CLEAR CLEAR CLEAR CLEAR CLEAR CLEAR CLEAR

Example 2

The aliphatic-aromatic copolyester used contained terephthalic acid, 25.1 mol % 2,2,4,4, tetramethyl-1,3 cyclobutanediol (50.1% cis isomer), 74.9% cyclohexanedimethanol. The inherent viscosity was measured to be 0.66. The copolyestercarbonate used consisted of bisphenol A diol, 20 mol % carbonic acid, 74.2 mol % isophthalic acid, and 5.8 mol % terephthalic acid. The inherent viscosity was measured to be 0.57.

The aliphatic-aromatic copolyester was dried at 90° C. and the copolyestercarbonate was dried at 120° C. Blends were prepared in a 19 mm Leistritz twin screw extruder. The polyesters were premixed by tumble blending and fed into the extruder and the extruded strand was palletized. The pellets were injection molded into parts on a Toyo 90 injection molding machine. The extruder was run at 350 rpms at a feed rate to give a machine torque between 80-100%. Processing temperatures used were in the range of 270° C. to 320° C. The compositions and properties of the blends are shown in Table 2.

TABLE 2 UNITS % Aliphatic-aromatic polyester % 100 90 80 70 50 30 0 % Copolyester carbonate % 0 10 20 30 50 70 100 Heat Deflection Temperature 264 Psi (deg C.) 82 86 96 101 117 129 151 Tensile Strength MPa 44 46 50 52 58 63 69 Tensile Break Elongation % 141 131 110 106 77 83 33 Flexural Modulus MPa 1427 1545 1721 1616 1537 1789 1904 Flexural Strength MPa 59 63 79 73 68 86 95 DSC Tg (Second Cycle) ° C. 109 112 119 124 139 151 176 Visual Clarity CLEAR CLEAR CLEAR CLEAR CLEAR CLEAR CLEAR

Example 3

The aliphatic-aromatic copolyester used contained terephthalic acid, 25.1 mol % 2,2,4,4, tetramethyl-1,3 cyclobutanediol (50.4 mol % cis isomer), 74.9% cyclohexanedimethanol. The inherent viscosity was measured to be 0.66. The polyarylate Ardel U100 was used in this example. It contains bisphenol A diol, 50 mol % isophthalic acid, and 50 mol % terephthalic acid. The inherent viscosity was measured to be 0.64.

The aliphatic-aromatic copolyester was dried at 90° C. and the polyarylate was dried at 120° C. Blends were prepared in a 19 mm Leistritz twin screw extruder. The polyesters were premixed by tumble blending and fed into the extruder and the extruded strand was pelletized. The pellets were injection molded into parts on a Toyo 90 injection molding machine. The extruder was run at 350 rpms at a feed rate to give a machine torque between 80-100%. Processing temperatures used were in the range of 270° C. to 340° C. The compositions and properties of the blends are shown in Table 3.

TABLE 3 UNITS % Aliphatic-aromatic polyester % 100 90 80 70 50 30 0 % Polyarylate % 0 10 20 30 50 70 100 Heat Deflection Temperature 264 Psi (deg C.) 82 90 98 105 118 133 163 Tensile Strength MPa 44 47 51 54 59 64 70 Tensile Break Elongation % 141 133 109 104 61 33 18 Flexural Modulus MPa 1427 1407 1455 1555 1667 1682 1787 Flexural Strength MPa 59 64 69 75 83 84 91 DSC Tg (Second Cycle) ° C. 109 116 121 131 142 163 190 Visual Clarity CLEAR CLEAR CLEAR CLEAR CLEAR CLEAR CLEAR

Counter Example 1

The aliphatic-aromatic copolyester used contained terephthalic acid, 50.5 mol % 2,2,4,4, tetramethyl-1,3 cyclobutanediol (54.0 mol % cis isomer), 49.5 mol % cyclohexanedimethanol. The inherent viscosity was measured to be 0.58. The copolyestercarbonate used consisted of bisphenol A diol, 51.6mol % carbonic acid, 44.6 mol % isophthalic acid, and 3.7 mol % terephthalic acid. The inherent viscosity was measured to be 0.56.

The aliphatic-aromatic copolyester was dried at 90° C. and the copolyestercarbonate was dried at 120° C. Blends were prepared in a 19 mm Leistritz twin screw extruder. The polyesters were premixed by tumble blending and fed into the extruder and the extruded strand was pellitized. The pellets were injection molded into parts on a Toyo 90 injection molding machine. The extruder was run at 350 rpms at a feed rate to give a machine torque between 80-100%. Processing temperatures used were in the range of 270° C. to 300° C. The compositions and properties of the blends are shown in Table 4.

The immiscibility of these blends is indicated by their haziness. Two Tg's are observed in the 50/50 blend which also indicates immiscibility. It is likely that the minor component in the other blends also has a second Tg which was too weak to be detected by DSC.

TABLE 4 UNITS % Aliphatic-aromatic polyester % 100 90 80 70 50 30 0 % Copolyester carbonate % 0 10 20 30 50 70 100 Heat Deflection Temperature 264 Psi (deg C.) 105 104 112 114 12 128 143 Tensile Strength MPa 48 49 52 54 58 61 65 Tensile Break Elongation % 90 99 63 66 49 76 88 Flexural Modulus MPa 1500 1561 1613 1677 1740 1865 1948 Flexural Strength MPa 66 66 70 73 80 85 93 DSC Tg (Second Cycle) ° C. 133 135 137 140 140 156 163 155 Visual Clarity CLEAR CLEAR HAZY HAZY HAZY HAZY CLEAR

Counter Example 2

The aliphatic-aromatic copolyester used contained terephthalic acid, 50.5 mol % 2,2,4,4, tetramethyl-1,3 cyclobutanediol (54.0 mol % cis isomer), 49.5 mol % cyclohexanedimethanol. The inherent viscosity was measured to be 0.58. The copolyestercarbonate used consisted of bisphenol A diol, 20 mol % carbonic acid, 74.2 mol % isophthalic acid, and 5.8 mol % terephthalic acid. The inherent viscosity was measured to be 0.57.

The aliphatic-aromatic copolyester was dried at 90° C. and the copolyestercarbonate was dried at 120° C. Blends were prepared in a 19 mm Leistritz twin screw extruder. The polyesters were premixed by tumble blending and fed into the extruder and the extruded strand was pelletized. The pellets were injection molded into parts on a Toyo 90 injection molding machine. The extruder was run at 350 rpms at a feed rate to give a machine torque between 80-100%. Processing temperatures used were in the range of 270° C. to 320° C. The compositions and properties of the blends are shown in Table 5.

The immiscibility of these blends is indicated by their opacity. In this example two Tg's are observed over a wider composition range which also indicates immiscibility.

TABLE 5 UNITS % Aliphatic-aromatic polyester % 100 90 80 70 50 30 0 % Copolyester carbonate % 0 10 20 30 50 70 100 Heat Deflection Temperature 264 Psi (deg C.) 105 108 113 116 129 136 151 Tensile Strength MPa 48 49 52 54 59 63 69 Tensile Break Elongation % 90 82 82 70 61 68 33 Flexural Modulus MPa 1500 1556 1575 1617 1732 1857 1904 Flexural Strength MPa 66 71 74 76 82 87 95 DSC Tg (Second Cycle) ° C. 133 135 136 139 139 170 176 168 167 166 Visual Clarity CLEAR OPAQUE OPAQUE OPAQUE OPAQUE OPAQUE CLEAR

Counter Example 3

The aliphatic-aromatic copolyester used contained terephthalic acid, 50.5 mol % 2,2,4,4, tetramethyl-1,3 cyclobutanediol (54.0 mol % cis isomer), 49.5 mol % cyclohexanedimethanol. The inherent viscosity was measured to be 0.58. The polyarylate Ardel U100 was used in this example. It contains bisphenol A diol, 50 mol % isophthalic acid, and 50 mol % terephthalic acid. The inherent viscosity was measured to be 0.64.

The aliphatic-aromatic copolyester was dried at 90° C. and the polyarylate was dried at 120° C. Blends were prepared in a 19 mm Leistritz twin screw extruder. The polyesters were premixed by tumble blending and fed into the extruder and the extruded strand was pelletized. The pellets were injection molded into parts on a Toyo 90 injection molding machine. The extruder was run at 350 rpms at a feed rate to give a machine torque between 80-100%. Processing temperatures used were in the range of 270° C. to 340° C. The compositions and properties of the blends are shown in Table 6.

In this example, clarity is obtained over part of the composition range and only one Tg is observed. This blend system appears to be on the borderline of forming a clear miscible blend.

TABLE 6 UNITS % Aliphatic-aromatic polyester % 100 90 80 70 50 30 0 % Polyarylate % 0 10 20 30 50 70 100 Heat Deflection Temperature 264 Psi (deg C.) 106 113 114 119 132 140 163 Tensile Strength MPa 48 50 52 56 60 65 70 Tensile Break Elongation % 59 82 67 39 23 26 18 Flexural Modulus MPa 1433 1480 1592 1592 1790 1787 1787 Flexural Strength MPa 66 66 68 77 90 91 91 DSC Tg (Second Cycle) ° C. 131 137 140 142 154 169 190 Visual Clarity CLEAR OPAQUE OPAQUE HAZY CLEAR CLEAR CLEAR

The invention has been described in detail with particular reference to preferred embodiments thereof, but it will be understood that variations and modifications can be effected within the spirit and scope of the invention. 

1. A polymer blend comprising: (A) about 5% to about 95% by weight of at least one polyester (A) which comprises: (i) a dicarboxylic acid component comprising: a) 70 to 100 mole % of terephthalic acid residues; b) 0 to 30 mole % of aromatic dicarboxylic acid residues having up to 20 carbon atoms; and c) 0 to 10 mole % of aliphatic dicarboxylic acid residues having up to 16 carbon atoms; and (ii) a glycol component comprising: a) 15 to 40 mole % of 2,2,4,4-tetramethyl-1,3-cyclobutanediol residues; and b) 60 to 85 mole % of 1,4-cyclohexanedimethanol residues, wherein the total mole % of the dicarboxylic acid component is 100 mole %, and the total mole % of the glycol component is 100 mole %; and (B) about 95% to about 5% by weight of at least one polymer (B) comprising a copolyestercarbonate of bisphenol A diol, and isophthalic acid residues, terephthalic acid residues, and carbonic acid residues; wherein said weight percentages are based on the total weight of the polymer blend.
 2. The blend of claim 1 wherein said polymer blend exhibits a single glass transition temperature.
 3. The blend of claim 1 wherein said polymer blend is miscible.
 4. The blend of claim 2 wherein said polymer blend is visually clear.
 5. A polymer blend comprising: (A) about 5% to about 95% by weight of at least one polyester (A) which comprises: (1) a dicarboxylic acid component comprising: a) 70 to 100 mole % of terephthalic acid residues; b) 0 to 30 mole % of aromatic dicarboxylic acid residues having up to 20 carbon atoms; and c) 0 to 10 mole % of aliphatic dicarboxylic acid residues having up to 16 carbon atoms; and (2) a glycol component comprising: a) 15 to 40 mole % of 2,2,4,4-tetramethyl-1,3-cyclobutanediol residues; and b) 60 to 85 mole % of 1,4-cyclohexanedimethanol residues, wherein the total mole % of the dicarboxylic acid component is 100 mole %, and the total mole % of the glycol component is 100 mole %; and (B) about 95% to about 5% by weight of at least one polymer (B) comprising a copolyestercarbonate of bisphenol A diol, and 0 to 90 mole % isophthalic acid residues, 0 to 60 mole % terephthalic acid residues, and 0 to 60 mole % carbonic acid residues; wherein said acid percentages of polymer (B) are based on a total of 100 mole % of acid units; and wherein said weight percentages of polymers in the blend are based on the total weight of the polymer blend.
 6. A polymer blend comprising: (A) about 5% to about 95% by weight of at least one polyester (A) which comprises: (1) a dicarboxylic acid component comprising: a) 70 to 100 mole % of terephthalic acid residues; b) 0 to 30 mole % of aromatic dicarboxylic acid residues having up to 20 carbon atoms; and c) 0 to 10 mole % of aliphatic dicarboxylic acid residues having up to 16 carbon atoms; and (2) a glycol component comprising: a) 20 to 40 mole % of 2,2,4,4-tetramethyl-1,3-cyclobutanediol residues; and b) 60 to 80 mole % of 1,4-cyclohexanedimethanol residues, wherein the total mole % of the dicarboxylic acid component is 100 mole %, and the total mole % of the glycol component is 100 mole %; and (B) about 95% to about 5% by weight of at least one polymer (B) comprising a copolyestercarbonate of bisphenol A diol, and 35 to 50 mole % isophthalic acid residues, 1 to 10 mole % terephthalic acid residues, and 40 to 60 mole % carbonic acid residues; wherein said acid percentages of polymer (B) are based on a total of 100 mole % of acid units; and wherein said weight percentages of polymers in the blend are based on the total weight of the polymer blend. 